GORHAM, Maine — A University of Southern Maine student was arrested late Wednesday night after what police described as an armed standoff at the Sigma Nu fraternity.

Alan-Michael Santos, 23, of Winchester, Mass., a junior business marketing major, is charged with felony terrorizing, criminal threatening with a weapon and reckless conduct with a weapon, as well as the civil offense of creating a police standoff, Detective Sgt. Dana Thompson of the Gorham Police Department said Thursday.

Police went to the fraternity at 24 School St. about 7:10 p.m. after another occupant of the building reported that a man was threatening and displaying a handgun, according to Thompson.

A USM police dispatcher confirmed that Santos was a member of the Sigma Nu fraternity, and that the handgun was loaded.

“We responded to the scene, set up a perimeter and moved people from their residences to safety,” Thompson said. “We evacuated local businesses, including three or four small restaurants, and removed some tenants and residents from apartment buildings.”

Police also called for the Cumberland County Sheriff’s Office tactical unit, which went to the scene with armed vehicles and special response team and attempted to negotiate a peaceful surrender.

While police worked to obtain a search warrant, Santos allegedly left the house unarmed about 11:30 p.m. and was taken into custody without incident, Thompson said. No injuries were reported.

Santos remained in Cumberland County Jail on Thursday morning, held on $15,000 bail. Arraignment is scheduled for Friday, Thompson said.

Police did execute a search warrant early Thursday morning and allegedly seized two handguns in the fraternity. Thompson could not immediately confirm whether the guns were loaded. Officers continued on Thursday to attempt to trace the owners of the weapons.

Thompson said police do not know why Santos allegedly created the standoff, but noted that the suspect declined to speak to police and has retained an attorney.

USM spokeswoman Judie O’Malley said Wednesday that the suspect, who locked himself in his room with the firearm, had been belligerent to his fraternity brothers before the incident, but Bob Caswell, USM’s director of public affairs, said Thursday that Santos’ motives remain unclear.

Caswell said USM’s emergency alert system sent out text alerts about the situation during the incident, as well as emails to dormitory students and members of all fraternities and sororities, while university staff made themselves available to talk to students and walked through campus buildings to ensure everyone knew of the situation.

The campus was never locked down, he said, because the standoff occurred off campus, because Gorham police responded so quickly and cordoned off the area and because the college had information that there was only one student involved.

Caswell said the university never previously experienced a crime of this severity. He said he is prohibited by federal law from talking about any disciplinary action taken against a student, but that the school would undertake an investigation and take into account the threat to public safety.

“Given the severity of this crime for which the student has been arrested, in any case such as this, we will hand down a decision shortly and we will be taking the incident very seriously because the safety of the students and our campuses is foremost,” Caswell said.